The goal of this project is develop a highly efficient active mixing hemodialyzer for patients in renal failure. We intend to replicate our active mixing membrane oxygenator (AMMO) technology currently under development to this device. Mass transfer in AMMO devices has proven to be 5-8 times more efficient than currently available static oxygenators, while not causing more blood damage than these clinical devices. In addition, the rotational movement of AMMO has resulted in it being a very efficient pump, thereby incorporating two basic functions in a single device. Active mixing functions to increase efficiency by imparting interstitial convection within the hollow fiber array and reducing blood phase resistance, resulting in increased mass transfer efficiency. In other words, motion of the fiber bundle disrupts the concentration boundry layer that impedes mass transfer across the membrane. This Phase I program is designed to evaluate the feasibility of our design. Specifically, using fabrication techniques developed for AMMO we will fabricate multiple active mixing dialyzer prototype variations with appropriate dialysis microporous fibers and dialysate fluid pathways. These units will then be evaluated in vitro per AAMI standards. Based on clearance data obtained we will select the most efficient dialyzer and fabricate a set of identical units for further functional evaluation. Finally, three ex-vivo animal trials to assess basic biocompatibility of the active mixing dialyzer are proposed. PROPOSED COMMERCIAL APPLICATION: Hemodialysis is required by over 200,000 Americans. The active mixing hemodialyzer has the potential to provide for more efficient, hence less time-consuming and lower biomaterials exposure, hemodialysis treatments. In addition, this device will pump blood thereby eliminating another element of current systems. It will be integratable into today's dialysis machines thereby eliminating the need for costly capital expenditures.